The present invention relates to domestic refrigerators and more particularly to an air circulation system for a refrigerator cabinet.
Conventional frostless-type refrigerators utilize forced refrigerated air flow to cool fresh food and freezer compartments. An electric fan draws refrigerated air across an evaporator coil with most of the air being forced into the freezer compartment and then returned to the evaporator. Some of the refrigerated air is delivered to the fresh food compartment through an air inlet opening therein. An adjustable damper is sometimes provided in the air inlet opening to adjust the amount of air directed into the refrigeration compartment to effect a greater or lesser amount of cooling.
Traditionally the control system for a top mount freezer/refrigerator consists of a separate control for each of the freezer and fresh food compartments. The control for the fresh food compartment is a sensing device (thermostat) located in the fresh food compartment which reacts to the supply air directed across it. The freezer section is governed by the relationship between the thermostat and the ratio of air directed into the freezer compartment. The ratio can be varied by an adjustable baffle which is located in the communicating duct between the freezer and fresh food compartments. By changing the baffle position, the air ratio between the two compartments is varied with a net result being that the freezer temperature is modified. However, the freezer temperature is also modified if the set point of the thermostat governing the fresh food compartment is changed. When the thermostat position is changed, the times required to fulfill the cooling needs of the fresh food compartment are modified, resulting in either a reduction or increase in the cooling system on/off time. Since the thermostat is the control for the cooling system, the fresh food compartment will be satisfied and the freezer section will only cool to a temperature governed by the air ratio and the cooling system run time.
U.S. Pat. No. 4,614,092 discloses an air baffle located in the refrigerator compartment which can be adjusted for varying the air flow into the refrigerator compartment.
U.S. Pat. No. 4,920,765 discloses a rotatable valve for controlling the amount of cooled air flowing from the freezer to the refrigerator compartment.